Hitherto, the method of performing the exposure of a photographic material by scanning laser beams thereon has been adopted as a means for transferring image information from MRI, X-ray CT or the like. As for the light source, semiconductor laser diodes endowed with high power and high stability have recently come into universal use, thereby allowing some latitude in the sensitivity of a photographic material as the output medium. On the other hand, a low coverage rate of silver is required of such a photographic material from the standpoint of rapid processing and environmental preservation. Therefore, there has been proceeding a movement to reduce the size of emulsion grains within the range of sensitivity allowed for maintaining the desired maximum optical density (Dmax).
However, when the sensitive material which is reduced in grain size and coverage rate of silver undergoes a laser scanning exposure, interference fringe bursts upon the eye, which results from the reflection of laser beams inside the photosensitive material. This interference fringe is called "non-contact interference fringe" in JP-B-06-10735 (the term "JP-B" as used herein means an "examined Japanese patent publication") and mentioned in detail therein. The patent publication cited above describes in the claim 1 three methods which enable complete dissolution of the interference fringe. However, it turned out that the backing layer (the method (2) described in the claim 1 of the above-cited reference), which is provided on the support surface situated on the side opposite to the photosensitive emulsions and defined as the near infrared absorption layer, had no function as the so-called absorption layer. Further, every working example of the above-cited reference has no description of effects to be produced by the subbing layer (the method (3) described in the claim 1 of the above-cited reference) defined as a near infrared absorption layer. Moreover, the subbing layer is arranged between the support and the photosensitive emulsion layer.
Actually, it was rather difficult to provide an absorption layer, that is, a dye layer on the same side of the support as the photosensitive emulsion layers. This is because it is necessary to design the absorption layer so that the dye incorporated therein may not substantially diffuse into other layers. Unless diffusion of the dye is prevented, not only the dye will exert harmful spectral effects upon other layers but also effects of the dye layer itself will be marred. However, in so far as the dye-added layer and another hydrophilic colloid layer are brought into contact with each other in a wet condition, it frequently happens that part of the dye added diffuses into the other hydrophilic colloid layers. Therefore, considerable efforts have so far been made to prevent the diffusion of dyes.
For instance, U.S. Pat. Nos. 2,548,564, 4,124,368, and 3,625,694 disclose the method of localizing dye molecules of the type which become anions by dissociation to a particular layer by making them be present together with a hydrophilic polymer mordant having the charge opposite in polarity to that of the dissociated dye molecules.
Also, the method of dyeing a particular layer with dye-adsorbed fine grains of metal salt is disclosed, e.g., in U.S. Pat. Nos. 2,719,088, 2,496,841 and 2,496,843, and JP-A-60-45237.
In addition, the method of dyeing a particular layer with a water-insoluble solid dye is disclosed, e.g., in JP-A-55-120030, JP-A-56-12639, JP-A-55-155350, JP-A-55-155351, JP-A-63-27838, JP-A-63-197943, JP-A-52-192716, European Patents 0 015 601, 0 323 729, 0 274 723, 0 276 566 and 0 299 435, World Patent 88/04794, JP-A-03-223747 and JP-A-04-352151.
However, with all the improved methods cited above, the problem of diffusion of dyes into layers other than the layer to which the dyes are to be fixed cannot yet be solved satisfactorily. Thus, coating a dye layer on the same side of a support as photosensitive emulsion layers is still a problem to solve. On the other hand, even if the coverage rate of silver or the size of emulsion grains are increased, suitability for rapid processing or desired Dmax cannot be attained. Accordingly, the acquisition of high suitability for rapid processing or the achievement of high Dmax, as things stand now, is incompatible with the dissolution of interference fringe.